From mboxrd@z Thu Jan  1 00:00:00 1970
From: Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [git pull] vfs pile 1
Date: Sun, 8 Jan 2012 15:04:30 -0800
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References: <20120105022318.GG23916@ZenIV.linux.org.uk>
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Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
To: Al Viro <viro@zeniv.linux.org.uk>,
	Miklos Szeredi <mszeredi@suse.cz>
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Hmm.

Al, Miklos, I just triggered the new inc_link() warning three times in
very close succession by just doing a simple

              perf record -f -e cycles:pp make -j

(I don't think the "perf record" part was actually required or
relevant, although it may have been instrumental in triggering just
the right timing)

This was in a fully built tree, I'm just checking

The warning trace looks like this:

  [ 6933.446125] ------------[ cut here ]------------
  [ 6933.446131] WARNING: at fs/inode.c:349 inc_nlink+0x30/0x40()
  [ 6933.446133] Hardware name: System Product Name
  [ 6933.446135] Pid: 22955, comm: perf Not tainted
3.2.0-03190-g972b2c719990 #72
  [ 6933.446137] Call Trace:
  [ 6933.446143]  [<ffffffff8102ee15>] warn_slowpath_common+0x75/0xb0
  [ 6933.446145]  [<ffffffff8102ef15>] warn_slowpath_null+0x15/0x20
  [ 6933.446147]  [<ffffffff810f1450>] inc_nlink+0x30/0x40
  [ 6933.446151]  [<ffffffff8116f333>] ext4_symlink+0x113/0x2c0
  [ 6933.446154]  [<ffffffff810e7b01>] vfs_symlink+0xa1/0xf0
  [ 6933.446157]  [<ffffffff810e7c03>] sys_symlinkat+0xb3/0xd0
  [ 6933.446159]  [<ffffffff810e7c31>] sys_symlink+0x11/0x20
  [ 6933.446162]  [<ffffffff816916a2>] system_call_fastpath+0x16/0x1b
  [ 6933.446164] ---[ end trace 550d4b2eb6b8fbc9 ]---

and the three warnings all triggered within 2/100th of a second of
that one (the last one had a timestamp of 6933.465678), so they are
probably all related to the same thing happening.

Any ideas?

                     Linus